This invention relates to an optical pick-up apparatus for optically performing at least one of selective recording of information onto a plurality of recording layers employed in an optical recording medium, and selective reproduction of information from the plurality of recording layers.
Optical pick-up apparatuses as above are known from, for example, Japanese Patent Application KOKAI Publications Nos. 5-189797 and 2-206037. When an optical pick-up apparatus disclosed in Japanese Patent Application KOKAI Publication No. 5-189797 optically performs at least one of recording of information onto a desired recording layer, and reproduction of information from the desired recording layer, optical beam emission means itself is inclined or moved parallel in order to radiate the desired recording layer with a light beam. Further, when an optical pick-up apparatus disclosed in Japanese Patent Application KOKAI Publication No. 2-206037 optically performs at least one of recording of information onto a desired recording layer, and reproduction of information from the desired recording layer, a beam splitter or a shielding plate is used in order to radiate the desired recording layer with a light beam, and light reflected from the desired r recording layer is guided by another beam splitter or a prism to a reflected-light detecting unit corresponding to the desired recording layer.
In the first-mentioned conventional optical pick-up apparatus, the structure for inclining or parallel-moving the optical beam emission means itself is very large and complicated. Accordingly, the optical pick-up apparatus is complicated in structure, and its entire body is inevitably large and heavy.
Also, in the second-mentioned conventional optical pick-up apparatus, the structure for combining the beam splitter, the shielding plate and the prism is very large and complicated. As a result, the optical pick-up apparatus is complicated in structure, which increases its manufacturing cost.
This invention has been derived from these circumstances, and an object of this invention is to provide an optical pick-up apparatus which h is small in scale, simple in structure and low in cost, which optically performs at least one of selective recording of information onto a plurality of recording layers employed in an optical recording medium, and selective reproduction of information from the plurality of recording layers.
In order to achieve the above-described object of the present invention, a first optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of an optical recording medium, and selective reproduction of information from the plurality of recording layers, performs switching in optical circuits which are each adapted to guide a light beam to a desired recording layer, using a movable mirror, to thereby perform selective recording of information onto the plurality of recording layers of the optical recording medium or selective reproduction of information from the plurality of recording layers.
In order to achieve the above-described object of the present invention, a second optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers, performs switching in optical circuits which are each adapted to guide a light beam to a desired recording layer, using a movable mirror which is movable in a direction of alignment of the optical recording mediums, to thereby perform selective recording of information onto the plurality of recording layers of the optical recording mediums or selective reproduction of information from the plurality of recording layers.
In order to achieve the above-described object of the present invention, a third optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of an optical recording medium, and selective reproduction of information from the plurality of recording layers, performs switching in optical circuits which are each adapted to guide a light beam to a desired recording layer, and guiding of the light beam to a desired recording track on the desired recording layer, using galvano mirrors, to thereby perform selective recording of information onto the plurality of recording layers or selective reproduction of information from the plurality of recording layers.
The galvano mirrors have a simple structure and can be controlled with high accuracy.
In order to achieve the above-described object of the present invention, in a fourth optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers, a plurality of reflection mirrors corresponding to the plurality of recording layers of the plurality of optical recording mediums are provided such that they are separated from each other in a direction of alignment of the plurality of optical recording mediums and in a direction parallel to the surfaces of the optical recording mediums; switching in optical circuits each adapted to guide a light beam to that one of the reflection mirrors arranged in the direction parallel to the surfaces, which corresponds to a desired recording layer, is performed using a movable mirror to thereby perform, via the plurality of reflection mirrors, selective recording of information onto the plurality of recording layers of the optical recording mediums or selective reproduction of information from the plurality of recording layers. The corresponding reflection mirror included in the plurality of reflection mirrors arranged in the direction parallel to the surfaces is adapted, if necessary, to further guide the light beam to that one of the reflection mirrors separated in the direction of alignment, which corresponds to a desired recording layer.
In order to achieve the above-described object of the present invention, in a fifth optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers provided on optical recording mediums and separated from each other in a direction perpendicular to the surfaces of the optical recording mediums, and selective reproduction of information from the plurality of recording layers, a light beam is entered in a direction parallel to the surfaces of the optical recording mediums for performing selective recording of information onto the plurality of recording layers separated in the direction perpendicular to the surfaces or selective reproduction of information from the plurality of recording layers.
Making a light beam to be entered in a direction parallel to the surfaces of the optical recording mediums as described above enables reduction of the size of the optical pick-up apparatus in a direction perpendicular to the surfaces of the optical recording mediums.
In order to achieve the above-described object of the present invention, a sixth optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers, performs switching in optical circuits which are each adapted to guide a light beam to a desired recording layer, using a biaxial movable mirror, to thereby perform selective recording of information onto the plurality of recording layers of the optical recording mediums or selective reproduction of information from the plurality of recording layers.
The use of the biaxial movable mirror not only enables execution of at least one of selective recording of information onto a plurality of recording layers of a single optical recording medium, and selective reproduction of information from the plurality of recording layers, but also enables simplification of the structure of an optical circuit which can perform at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers.
In order to achieve the above-described object of the present invention, a seventh optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers, performs switching in optical circuits which are each adapted to:guide a light beam to a desired recording layer, using a biaxial movable mirror which can be inclined in a direction of alignment of the plurality of optical recording mediums and in a direction parallel to the surfaces of the optical recording mediums to thereby perform selective recording of information onto the plurality of recording layers of the optical recording mediums or selective reproduction of information from the plurality of recording layers.
The use of the biaxial movable mirror which can be inclined in both the direction of alignment and the direction parallel to the surfaces, not only enables execution of at least one of selective recording of information onto a plurality of recording layers of a single optical recording medium and selective reproduction of information from the plurality of recording layers, but also permits the structure of an optical circuit to be made compact, which circuit can perform at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers.
In order to achieve the above-described object of the present invention, in an eighth optical pick-up apparatus, according to the invention, which optically performs at least one of selective recording of information onto a plurality of recording layers of a plurality of optical recording mediums arranged in layers, and selective reproduction of information from the plurality of recording layers, a plurality of reflection mirrors corresponding to the plurality of recording layers of the plurality of optical recording mediums are provided such that they are separated from each other in a direction of alignment of the plurality of optical recording mediums and in a direction parallel to the surfaces of the optical recording mediums. Switching in optical circuits which are each adapted to guide a light beam to that one of the reflection mirrors arranged in the direction parallel to the surfaces, which corresponds to a desired recording layer, is performed using a movable mirror to thereby perform, via the plurality of reflection mirrors, selective recording of information onto the plurality of recording layers of the optical recording mediums or selective reproduction of information from the plurality of recording layers; and the corresponding reflection mirror included in the plurality of reflection mirrors arranged in the direction parallel to the surfaces is adapted, if necessary, to further guide the light beam to that one of the reflection mirrors separated in the direction of alignment, which corresponds to a desired recording layer.
Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter.